I have one. It was disappointing. I type very fast and if the keyboard is not really precise, soft and "springy" (oh, I know what I mean but...), speed turns into frustration. You can only type very fast when you have a fine keyboard, or the "notes in the piano" get tangled.
I plan to buy a hard, small and thin keyboard. I think Sarah or Cheyenne or NiaTrue recommended one, I don't remember now who did. I will search again in the threads and try to get one.
As Boris said, you need to place them in a solid surface, not in your knees.

But if you need to use the keyboard occasionally and you want to fold it and put it into a small place in your carry bag, it may do. If you have to type for a long time, I would not recommend it.

Boris and Paula-t, thanks for your thoughts. I appreciate it. I am not a typist but I don't want to make the process more difficult than it already is. Convenience was in my mind Paula, being able to fold and take along. I will look at the variety, especially the smaller keyboards, available at the tech stores in my area and test them if they let me.

It's pretty much the exact length of the EE and, yes, "super slim." It's very much like the Apple keyboard. A few pictures in comparison to the EE and the case I have (fits both EE and keyboard). I've never wanted a folding keyboard because I guess I only saw them years ago when they first came out, and they didn't "lock" into place very well (meaning you still had to use them on a solid surface) but someone here mentioned a new one that looked quite solid and verified you could use it on the lap.

I agree with paula-t, the key action on the flexibles that I tried were terrible. I have rheumatoid arthritis and they would never work for me. I purchased the one sarah is showing here (from ebay), and it works great. Nice light touch. Easy on the hands.

Hi Sarah, evidently this keyboard is no longer available, but they did have one "used-Like new" available at a reasonable price through Amazon. I needed ink so it comes with free shipping. Thanks for all the input.